Snap switch actuating device for use in a mechanical memory drum



1 K. W. KURZ SNAP SWITCH ACTUATING DEVICE FOR USE IN A MECHANICAL MEMORY DRUM Filed Jan. 29, 1962 IN V EN TOR. KARL WILL Y KURZ AGENTS United States Patent 3,151,509 SNAP SWTTCH ACTUATING DEVICE FOR USE IN A MECHANICAL MEMGRY DRUM Karl W. Kurz, Richardson, Tex, assignor to Qollins ladio Company, Cedar Rapids, Town, a corporation of own Filed I 2.9, 1962, Ser. No. 169,523 2 Claims. (Ci. 74-568) This invention pertains to switches and particularly to switch actuators that are adjustable for determining which combination of switches is operated for each of their selected positions.

Switch actuators according to this invention are particularly applicable to the tuning systems of radio receivers or of transmitters that have many selectable channels. These equipments may have actuators for operating switches in certain combinations to provide means for tuning quickly to a relatively small number of channels that are preselected from the total number of channels available. The switches are often part of the automatic tuning control circuits of the equipments.

Prior devices for tuning have included cams mounted on rotary actuators. The cams positioned such that for different rotary positions of the actuators, they operate spring-return tuning control switches to difierent positions. However, easy quick means for changing the mounting positions of cams on the respective actuators for selecting different switch combinations is provided by the new actuator of this invention.

An object of this invention is to provide a compact switch actuator that may be set easily and quickly to operate any desired possible combination of switches for any particular position of the switch actuator.

The following description and the appended claims may be more readily understood with reference to the accompanying drawings in which:

FIG. 1 is a top view of the switch mechanism of this invention in which the top cover has been partly cut-away to show the cams of the actuator;

FIG. 2 is a cross-section view of a portion of a disk actuator; and

FIG. 3 is an exploded oblique view of an actuator disk.

A preferred embodiment of this invention comprises a plurality of disk actuator assemblies mounted on a common rotary control shaft. The disk actuator assemblies have in their peripheral edges cylindrical cavities in which firm balls are mounted. The cavities are disposed trans verse the direction of rotation of their respective disk. When the disks are rotated, balls that are positioned in one end of each of the cavities pass in line with plungers of switches that are mounted adjacent the respective disks. That portion of the wall of each of the cavities that is on the outer circumference of the respective disk is open so that the ball contained in the cavity protrudes suihciciently for it to function as a cam for operating an adjacent switch when the ball is carried into alignment with the operating plunger of the switch.

A resilient ring, such as an O-ring made of rubber or synthetic rubber, is mounted in a groove within each disk assembly so that it intersects a small portion of the middle of the wall of each cavity. The protrusion of the O-ring into each of the cavities is sufficient to retain each of the balls in either end in which it is positioned. Moderate force applied to any ball in the direction of the other end of the cavity causes the O-Iing at the point continguous the ball to compress to let the ball pass the middle of the cavity. As the ball passes the middle, the O-ring expands back to its normal shape to flip the ball to the other end of the cavity and to retain it there. A slot in the cover of the disk assembly provides ready 3,151,569 Patent-ed Got. 6, 1954 access to the balls, or cams, for moving them in or out of their operate positions. A dial on the shaft displays a. number through the slot to indicate which switch position corresponds to the balls that are accessible.

in more detail, the switching device of FIG. 1 includes a tuning shaft it which is rotatably mounted within the dust cover 11. The shaft is positively positioned by a usual spring and ball detent 12 in response to the shaft being rotated to indexed positions by control knob 13. As the shaft is rotated, a plurality of actuator or cam disk assemblies mounted coaxially on the shaft are rotated to position cam balls relative to switches that are mounted with plungers almost touching peripheries of respective cam actuator disks. The top of the dust cover 11 is shown partly cut-away to expose cam disks 14 and 15.

Each of the cam disks have evenly spaced cylindrical cavities 16 in their peripheral edges for receiving cam balls 17. The cam balls are a slip fit transverse the disks, but are retained so they do not move substantially in the direction of rotation of the disks. The cam ball 13 of disk 15 is shown positioned for operating switch 19. Each of the balls that is to operate a switch for a selected position of the actuator disks is positioned in that end of its respective cavity for placing the ball in line with the cam follower or plunger of the respective switch. The ball 18 that is shown in line with the plunger 21 of switch 19 operates against the roller or cam follower 29 that is mounted on the end of plunger 21 to push the plunger inward to an operate position. The ball 24 of disk 1 is positioned in the opposite end of its cavity so that it is not in line with switch 22 and so that for this particular position of the switch shaft it, the plunger of switch 23 is extended in its release position.

As shown in the exploded view of actuator disk assembly 14 in FIG. 3, each actuator disk assembly comprises a pair of notched disks 25-26, an O-ring 27, and a pair of retaining disks 28-29. Each notched disk 2526 has a notch for each indexed position of shaft 10 as determined by detent 12. Each of the notches 30 has a cross-section as viewed from the face of the disk that is slightly greater than a semicircle so that outwardly facing transverse slots have widths less than the diameter of the cam balls to retain them and have a portion of each ball protrude outwardly from the edge of the respective disk. An annular groove 31 is disposed concentrically within the inner face of each of said notched disks. The outer wall of the groove extends into the peripheral notches so that the bottom of each notch has a portion 32 facing inwardly cut away to form a central opening between the notches and a cavity containing the O-ring. The O-ring 27 fits into the mating grooves 31 of notched disks 25 and 26 when they are mounted on the shaft 10 with their groover faces contiguous. The notched disks have keyed openings 33 for mounting the disks on the shaft 10 such as they will be constrained to rotate with the shaft. The notched disks are retained tightly together on the shaft and the cam balls are retained within the notches of the disk by retaining plates 28 and 29 that are mounted against the outer faces of the notched disks and are fixed on the shaft by set screws 35 within their bushings 34. As clearly shovm in FIG. 2, the width of each of the notched disks is approximately equal to the diameter of a cam ball. The O-ring 27 restricts the central portion of the cavity so that the ball is retained in whichever end of the cavity it is placed.

A slot 37 along the top of the dust cover in line with the tuning shaft 1% permits access by any slender tool such as the tool 36 of FTG. 2 to any of the balls that are positioned below the slot. The indicator wheel 38 which is securely mounted to shaft 10 has numbers to be viewed through the slot for determining which balls correspond a 1 a to the indexed positions of the control knob 13. Through reference to a chart, the shaft can very readily be rotated to a desired position as shown by indicator wheel 3%, and the balls for thatrshaft position very quickly positioned in their cavities as required for operating a desired combination, of switches in response to the control knob 'being turned to a corresponding reading. Because of the resiliency of the O-ring, the ball tends to flip into the desired position after it is forced past the middle of its respective cavity.

Although this invention has'been described Wiill'lfiSPGCi. to a particular embodiment illustrated in the accompanying drawing, it is to be understood that the arrangement of movable cams captive Within cavities and having resilient means for retaining the cams either in or out of planes for operating switches may be applied to different switch configurations according to modifications of this invention by ways obvious to those skilled in the art and still be within the spirit and scope of the following claims. 7

I claim: 1. A rotary annular actuator member with indexed rotary positions, a control device with an actuator plunger having a released position and an operated position, said actuator member having a plurality of elongated cavities of constant cross section spaced apart circumferentially on said member at said indexed rotary positions, the wall of each of said cavities having a longitudinal open slot transverse the direction of rotation of said member and facing on a radial line of said member,

an actuator cam mounted in each of said cavities, each of said cams having a portion protruding from said respective slot, said cams being constrained in said cavities inrthe direction of rotation of :said member but being a sliding fit for movement along said slot,

resilient retaining means mounted to subtend transversely a portion of the Wall of each cavity so as to decrease slightly the cross section thereof at the approximate midpoint between the ends of each of said cavities, thereby to retain each of said cams in a fixed position between said resilient retaining means and that end of the respective cavity into which said cam has been placed, any selected ones of said cams for operating said control device being readily positioned in the ends of respective cavities that place said protruding portions of said selected cams in alignment on a circumference of said rotary member, said control device being mounted with its actuator plunger in the path of the protrusions of said cams in alignment on said circumference, said actuator being operated in response to engagement of said plunger by said selected cams as said actuator member is rotated to corresponding ones of said indexed positions,

any of said selected cams being readily transferred by a flipping action to the opposite ends of their respective cavities by application of moderate force along respective slots to remove them'i'rom the path of said actuator plunger,

and said cams within said opposite ends of said cavities being retained by said resilient means outside said path.

2. In a selector switch of thetype having a rotary shaft with detent means for positively positioning said shaft in successive selectable rotary" positions, a plurality of disk assemblies spaced apart coaxially on said shaft and constrained to rotate therewith, a plurality of spring-return switches, at least one of said spring-return switches being mounted with its operating plunger adjacent to the periphery of each of said disk assemblies, and said switches being operated by rotatively positioning protrusions of peripheries of said disk assemblies in' line with said plunger, V V 1 each of said disk assemblies comprising a pair of notched disks, a pair of retaining disks, a resilient ring, and a plurality of firm actuator balls, said actuator balls being readily positioned for operating any predetermined combination of said switches, each of said notched disks having'sirnilar peripheral notches circumferentially spaced to correspond to said selectable rotary positions of the shaft, the cross-sections of each ofsaid notches as viewed from the parallel faces of its respective notched disk being a segment of a circle greater than a semicircle, I each of said notched disks having an annular groove concentrically disposed in one face thereof, the outer radius of said groove being slightly greater than the radius of the circle defined by the bottom of said notches, said notched disks for each of said disk assemblies being assembled on a shaft with their grooved faces contiguous, said resilient ring being confined within the mating grooves of the faces of said assembled pairs, the notches of said assembled pairs being aligned to form longitudinal sections of cylindrical cavities in the peripheral edges of 'said' disk assemblies for receiving said balls, each of said balls having a slightly smaller diameter than the di-' ameters'of each of said cylindrical cavities, a portion of the periphery of a respective resilient ring being disposed in that portion of said groove in the middle of the bottom of each of said cavities, a pair of retaining disks being adjacent to respective outer surfaces of an assembled pair of said notched disks to confine one of said balls in each of said cavities, said resilient ring retaining each of said balls in a fixed position within a respective notch of one of said notched disks, any one of said balls being readily flipped by moderate force from the disk assemblies of said resilient ring to the opposite notch in the adjacent notched disk, and

the operating plunger of each of said switches being aligned with a particular one of the notched disks] of the respective one of said disk assemblies in the path of the protruding surfaces of any balls positioned therein, each of said switches being operated in response to said shaft being rotated to a position corresponding to that in whichia ball is positioned in a notch aligned with its respective plunger.

References Cited in the file of this patent UNITED STATES PATENTS' 1,863,414 Pratt June 14, 1932 2,255,012 Lake et a1. Sept. 2, 1941 2,536,133 Klammer et al. Jan. 2, 1951 

1. A ROTARY ANNULAR ACTUATOR MEMBER WITH INDEXED ROTARY POSITIONS, A CONTROL DEVICE WITH AN ACTUATOR PLUNGER HAVING A RELEASE POSITION AND AN OPERATED POSITION, SAID ACTUATOR MEMBER HAVING A PLURALITY OF ELONGATED CAVITIES OF CONSTANT CROSS SECTION SPACED APART CIRCUMFERENTIALLY ON SAID MEMBER AT SAID INDEXED ROTARY POSITIONS, THE WALL OF EACH OF SAID CAVITIES HAVING A LONGITUDINAL OPEN SLOT TRANSVERSE THE DIRECTION OF ROTATION OF SAID MEMBER AND FACING ON A RADIAL LINE OF SAID MEMBER, AN ACTUATOR CAM MOUNTED IN EACH OF SAID CAVITIES, EACH OF SAID CAMS HAVING A PORTION PROTRUDING FROM SAID RESPECTIVE SLOT, SAID CAMS BEING CONSTRAINED IN SAID CAVITIES IN THE DIRECTION OF ROTATION OF SAID MEMBER BUT BEING A SLIDING FIT FOR MOVEMENT ALONG SAID SLOT, RESILIENT RETAINING MEANS MOUNTED TO SUBTEND TRANSVERSELY A PORTION OF THE WALL OF EACH CAVITY SO AS TO DECREASE SLIGHTLY THE CROSS SECTION THEREOF AT THE APPROXIMATE MIDPOINT BETWEEN THE ENDS OF EACH OF SAID CAVITIES, THEREBY TO RETAIN EACH OF SAID CAMS IN A FIXED POSITION BETWEEN SAID RESILIENT RETAINING MEANS AND THAT END OF THE RESPECTIVE CAVITY INTO WHICH SAID CAM HAS BEEN PLACED, ANY SELECTED ONES OF SAID CAMS FOR OPERATING SAID CONTROL DEVICE BEING READILY POSI- 